Pressurized mortar pot apparatus

ABSTRACT

A two-part pressure vessel includes an upper section containing a pressure tank, which is secured to a cylindrical lower section by a clamp and flange arrangement. A charge of mortar is placed in the lower section, after which the pressure vessel is assembled. The vessel contains a reciprocable piston that is carried by the upper section, and which is driven toward the mortar charge by compressed air drawn from the pressure tank. The lower section has a mortar discharge outlet, which is connected to a trowel or nozzle by a flexible conduit made of hose or other flexible material. Mortar is withdrawn from the pressure vessel upon demand by operating a valve controlling the flow of compressed air to the region behind the piston, the pressure acting on the piston being regulated to ensure even feeding of the mortar. The piston rod has a bleed passage extending therethrough, whereby air trapped beneath the piston can be released to help ensure even feeding of the mortar, and a relief valve is provided to relieve air pressure behind the piston when desired.

United States Patent [191 Giovannozzi Primary Examiner-Allen N. KnowlesAssistant Examiner-Larry Martin Attorney, Agent, or FirmBacon & ThomasOct. 22, 1974 [5 7] ABSTRACT A two-part pressure vessel includes anupper section containing a pressure tank, which is secured to acylindrical lower section by a clamp and flange arrangement. A charge ofmortar is placed in the lower section, after which the pressure vesselis assembled. The vessel contains a reciprocable piston that is carriedby the upper section, and which :is driven toward the mortar charge bycompressed air drawn from the pressure tank. The lower section has amortar discharge outlet, which is connected to a trowel or nozzle by aflexible conduit made of hose or other flexible material. Mortar iswithdrawn from the pressure vessel upon demand by operating a valvecontrolling the flow of compressed air to the region behind the piston,the pressure acting on the piston being regulated to ensure even feedingof the mortar. The piston rod has a bleed passage extendingtherethrough, whereby air trapped beneath the piston can be released tohelp ensure even feeding of the mortar, and a relief valve is providedto relieve air pressure behind the piston when desired.

10 Claims, 4 Drawing Figures PAKMU, um 22197-1 3, 43 ,025

SHEEI 2 BF 3 PRESSURIZED MORTAR POT APPARATUS BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relatesgenerally to apparatus for use in placing mortar on a base prior to thelaying of a course of brick or the like. More particularly, it relatesto apparatus for feeding mortar to a base, evenly and continuously upondemand.

2. Description of the Prior Art The laying of brick and the like is anancient art, traditionally involving as a first step the application ofa layer of mortar on the base by a workman who uses a hand trowel totransport the mortar a small quantity at a time from a board orcontainer. When the layer of mortar is in place a course of brick islaid, and the process is then repeated until the desired wall structureis obtained.

Over the years efforts have been made at speeding the traditional manualbricklaying process, and many devices have been proposed to aid thebricklayer in his efforts. A great saving of time could be achieved if asatisfactory apparatus was available for laying the mortar on a base,prior to placing of the course. To be successful such apparatus shouldbe operational upon demand by the worker, and more importantly should beeffective to place an even layer of mortar where required. In addition,the apparatus should be capable of supplying mortar for at least severalhundred bricks without refilling, and should be easily refillable whenempty. No fully satisfactory apparatus of this type has been thus farproposed, and thus a need therefor now exists in the construction field.The pressurized mortar pot of the present invention is intended tosatisfy that need.

SUMMARY OF THE INVENTION The pressurized mortar pot of the presentinvention includes a two-part pressure vessel, including a generallycylindrical lower section having an external flange on its upper end,and which is adapted to receive a charge of mortar. An upper vesselsection is receivable on the lower section, andhas a mating externalflange on its lower end. A split band clamp is carried by the uppersection, and is engageable with the flanges to se cure the two vesselsections together.

The upper vessel section includes a pressure tank for receivingcompressed air, and an axial, cylindrical housing extends verticallythrough said pressure tank and receives a piston rod that isreciprocally mounted therein. A gland sealing arrangement is provided toprevent leakage around the piston rod, and the lower end of the pistonrod carries a circular piston plate having an annular resilient gasketmolded thereto. The gasket includes an upstanding lip on the rear orupper side of the piston plate that engages the inner wall of thecylindrical lower vessel section to form an air-tight seal when theregion behind the piston is pressurized, and a depending lip on thelower or front side of the piston plate that acts as a wiper to scrapethe vessel walls of mortar as the piston moves downwardly.

The pressure tank is initially charged with compressed air from asuitable source through a T-fitting having one portion of a quickdisconnect coupling mounted on one leg thereof. After the pressure tankis charged the supply hose is disconnected, and an operating hose isconnected to the T-fitting and leads through a foot-operated controlvalve and a pressure regulator to the region within the pressure vesselbetween the upper or rear side of the piston and the lower side of thepressure tank.

The bottom of the pressure vessel has a mortar discharge fittingthereon, connected by a hose or other suitable conduit to a trowel ornozzle of suitable design. With the pressure vessel containing a chargeof mortar and the pressure tank supplied with compressed air, theworkman moves the trowel or nozzle to the location where it is desiredto place mortar, and then operates the foot-operated control valve. Whenthe control valve is opened, air is transferred from the pressure tankto the region above the piston, the pressure regulator serving toestablish a preset, even level of pressure within the pressure vessel.This even level of pressure acts on the piston to feed mortar to thetrowel or nozzle at an even pace, where the workman spreads it asdesired. When adequate mortar has been placed, the workman simplyreleases the foot pedal and the control valve closes automatically,thereby preventing the passage of further compressed air to the pressurevessel and thus stopping the flow of mortar.

In some instances, it is possible for air to become trapped between thepiston and the mortar charge, usually during the filling of the lowersection of the pressure vessel. Such trapped air can cause the piston toact in a spongy manner, resulting in unevenness in the feeding ofmortar, and occasionally in difficulty in starting and stopping mortarflow. The invention includes a unique means of eliminating such pocketsof trapped air, whereby an even mortar flow is assured.

The piston rod has an axial bleed passage extending completelytherethrough, with the lower end of said passage opening on the frontface of the piston. The upper end of the passage is equipped with aneasily operable closure means, either in the form of a valve or aneasily removed and inserted threaded plug. After the mortar charge hasbeen placed and the pressure vessel closed, and before the mortar pot isplaced in service, the upper end of the bleed passage is opened and thepiston chamberis pressurized. The initial downward movement of thepiston will then be effective to drive any trapped air outwardly throughthe bleed passage from beneath the piston, after which the upper end ofthe passage is closed, and the mortar pot is ready for use.

When the mortar supply is exhausted, the pressure above the piston isrelieved through a relief valve mounted on the sidewall of the lowervessel section, and the pressure vessel is then opened by removing thesplit band clamp. A new mortar charge is placed in the pressure vessel,the vessel is reassembled, the pressure tank repressurized, and theapparatus is again ready for service. The split band clamp and flangearrangement is easily operated in a minimum of time, thus facilitat ingthe refilling operation.

While the present mortar pot can, of course, be utilized in manydifferent locations, in the preferred embodiment of the invention suchis mounted on a travelling scaffold, which also includes a platform uponwhich the bricklayer stands. The scaffold is designed to move along thebase line of the brick structure being constructed, carrying the mortarpot therewith. Thus, the workman can easily use the mortar pot of theinvention to lay mortar on the whole length of a base before the firstbrick of the course is placed in position, whereby a true assembly linetype of bricklaying is made possible.

It is the principal object of the present invention to provide anapparatus for evenly and continuously applying mortar to a base uponwhich a course of brick or the like is to be laid.

Another object is to provide a pressurized mortar pot for use inapplying mortar to a base, wherein the mortar is fed evenly from whenthe first portion of a mortar charge is discharged until when the lastportion of the charge leaves the mortar pot.

A further object of the invention is to provide a pressurized mortar potutilizing a piston operated by compressed air to evenly and continuouslyfeed mortar through a discharge conduit.

Yet another object is to provide a mortar pot having means for bleedingair pockets from between the piston face and the mortar charge, wherebyto assure an even feeding of the mortar.

Still another object is to provide a mortar pot that can be easily andquickly refilled, and which is rugged in construction and substantiallymaintenance free.

Other objects and many of the attendant advantages of the presentinvention will become readily apparent from the following Description ofthe Preferred Embodiment, when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary elevationalview, showing the pressurized mortar pot of the invention mounted on atravelling scaffold, with a mortar charge in place and the piston rod inits initial, withdrawn position;

FIG. 2 is an end elevational view, partly in section, taken on the line2-2 of FIG. 1;

FIG. 3 is an enlarged, fragmentary vertical sectional view through thepressurized mortar pot of FIGS. 1 and 2, showing details of theconstruction thereof; and

FIG. 4 is a diagrammatic view showing the arrangement of the variousvalves and pressure control devices of the invention, and the dischargeconduit and trowel.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, atravelling scaffold is indicated generally at 2, and includes guides 4and 6 upon which the wheels 8 and 10 of a rectangular base 12 rest. Eachset of wheels 8 and 10 is mounted on a shaft 14, and one of the shafts14 has a sprocket wheel 16 mounted thereon that is engaged by a drivechain 18 leading to a drive sprocket wheel 20 on a hydraulic motor 22.It is thus seen that the travelling scaffold 2 can be moved along theguides 4 and 6 by activating the hydraulic motor 22, said motor beingoperable in either a forward or a rearward direction. The guides 4 and 6extend parallel to where it is desired to construct a wall of brick orthe like, and thus the scaffold 2 is movable horizontally along the wallin either direction while such is under construction.

Extending upwardly from the base 12 are two pairs of upright structuralmembers 24, connected on inner members at their upper ends by a bridgingmember 26. Two hydraulic cylinders 29 are mounted vertically along theouter side of upright members 24. Upper ends of said members 25 havestub-shafts 27 mounted on the under side of cross member 26.

Mounted in the channels 25 are four flanged load runners 32, upperwheels 34 are mounted on the stub shafts 27 in alignment with the backof deck 42. A chain 36 is engaged over a pair of sprocket wheels 34, andconnected to the deck 42 to be transported vertically thereby is aplatform 38. The platform 38 includes stabilizer rollers 32 engaged invertical edges of the upright members 25, and has a deck 38 upon which aworkman can stand. A drive motor 44 is connected to the hydraulic pump28 by a coupling 46, and is operable to move the platform 38 eitherupwardly or downwardly.

The controls for both of the drive motors 22 and 44 are placed withinreach of a workman standing on the deck 42, and thus by operating suchcontrols the workman can move the platform 38 both vertically andhorizontally along the line of the wall to be constructed.

Mounted on the platform 38 are two spaced bracket arms 48 terminating attheir upper ends in aligned, V- shaped channels 50, the arms 48 thusbeing arranged to travel vertically and horizontally with the platform38. Supported by the bracket arms 48 is the pressurized mortar pot ofthe invention, indicated generally at 100.

The travelling scaffold 2 is not a part of the pressurized mortar pot ofthe invention, except insofar as it serves to support the same in amanner to make it movable along and vertically of a wall beingconstructed. Hence, the scaffold 2 will not be described in furtherdetail herein. It is also to be understood that the mortar pot 100 isnot limited to use with a travelling scaffold like that indicatedgenerally at 2, but that rather the same could be mounted on anystructure or by whatever means suitable to the conditions whereunderbricks or the like are to be laid.

The pressurized mortar pot 100 includes a pressure vessel 102, comprisedof a generally cylindrical lower section 104 and an upper section 106.The lower section 104 includes a cylindrical sidewall 108 having apressure dome 110 welded or otherwise secured to the lower end thereof,the dome 110 having a central discharge opening 112 therein to which anelbow fitting 114 is secured. The lower section 104 terminates at itsupper end in an external, tapered flange 116, and has diametricallyopposed, aligned V-shaped supports 118 secured to the exterior thereofthat are received in the V-shaped brackets 50 to support the mortar pot100 on the travelling scaffold 2.

The upper vessel section 106 is dome shaped, and has an external,tapered flange 120 secured to the lower end thereof, the flange 120mating with the flange 116, and having an annular groove 122 therein forreception of an O-ring seal 124. Secured to the upper section 106 andprojecting outwardly therefrom is a bracket 126, which supports a hingebolt 128 that connects the rear end portions of the semicircular halves130 and 132 of a split band clamp 134. The band clamp 134 is engageablewith the tapered flanges 116 and 120 to secure the upper and lowervessel sections 106 and 104 in assembled relationship, the free ends ofthe band halves 130 and 132 respectively having radial flanges 136 and138 thereon, through which a securing bolt 140 extends. The pressurevessel 102 is thus easily opened for filling merely by removing the bolt140, and then lifting off the upper vessel section 106. Because thesplit band clamp 134 is mounted on the upper vessel section 106 suchcannot be displaced, and is automatically in position for reassemblywhen the flanges 116 and 120 are engaged.

Received and welded within the upper vessel section 106 is a dishedplate 142, whereby a pressure tank 144 is formed within the section 106.Compressed air is supplied to and withdrawn from the pressure tank 144through a nipple 146, to which one of the aligned legs 148 of aT-f1tting 150 is secured. The other aligned leg of the T-fitting 150 isconnected to a pressure gauge 152 through a valve 154, and the centerleg of the fitting has one half 156 of a conventional quick disconnectcoupling mounted thereon.

The upper end of the section 106 has a central opening 158 therein,which is in axial alignment with a like opening 160 disposed centrallyof the dished plate 142. A gland 162 internally threaded at its oppositeends is welded in the opening 158, and is in alignment with a sleeve 164welded in the opening 160, the sleeve 164 being internally threaded atits upper end. A nipple 166 is threaded at its opposite ends into thegland 162 and the sleeve 164, whereby a cylindrical housing 168extending through the pressure tank 144 is completed. Reciprocallyreceived through the housing 168 is a piston rod 170, the gland 162receiving packing 172 about the upper end of the piston rod 170, whichpacking is compressed by a collar 174 threaded into the upper end of thegland. The packing 172 is effective to prevent leakage through thecylindrical housing 168, and at the same time allows reciprocal motionof the piston rod 170.

The lower end of the piston rod 170 has a reduced diameter, threadedportion 176, on which is received a circular plate piston 178 having acentral opening therein through which the portion 176 is received. Thepiston 178 is secured to the piston rod by a nut 180, and has aresilient gasket member 182 molded to the upper or rear face thereof. 1

The gasket 182 includes a radial annulus 184 having an upstandingperipheral tapered lip 186 on the rear or upper face thereof, and adownwardly extending peripheral lip 188 that includes a cylindricalportion 190 which engages over the edge of the piston 178, and a taperedportion 192. The upstanding lip 186 is of larger diameter than theinterior diameter of the lower vessel section 104, and acts as apressure seal. When compressed air is admitted to the region above thepiston 178, the lip 186 is forced outwardly into tight engagement withthe wall of the vessel section 104.

The downwardly extending lip portion 192 functions as a wiper duringdownward or forward motion of the piston 178, to scrape mortar from thecylindrical wall of the lower section 104. The taper on the lip portion192 is effective upon engagement with the mortar charge 194 duringmovement of the piston 178 to force the sharp tip of the lip 188 intoengagement with the vessel wall, whereby the desired scraping or wipingaction is assured. By thus scraping mortar from the cylindrical wall ofthe vessel 102 during movement of the piston 178 a smooth surface forengagement by the air pressure sealing lip 186 is assured, and theundesired entry of air below the piston 178 is prevented.

The presence of air pockets between the piston 178 and the mortar charge194 is undesirable, since air is compressible and thus will cause aspongy action in the piston. Such spongy action makes it difficult toproperly control mortar flow, especially upon start-up and termination.While the gasket 182 is designed to prevent the formation of such airpockets during operation of the mortar pot apparatus, air can becometrapped beneath the piston 178 during filling of the pot with a mortarcharge 194. Thus, the mortar pot 100 includes a means whereby suchtrapped air pockets can be eliminated.

Referring to FIG. 3, the piston rod is provided with an axial bleedpassage 196 that extends throughout its length, the upper end of thepassage 196 being internally threaded, and the lower end thereof openingon the front face of the piston 178. Thus, when the passage 196 is openand compressed air is admitted to the region above or behind the piston178, any pockets of air trapped between the mortar charge 194 and theface of the piston 178 can escape through said bleed passage.Thereafter, the bleed passage 196 is closed at its upper end, and themortar pot 100 is ready to be placed in service.

The upper end of the bleed passage 196 can be closed by a simplethreaded plug, if desired. In the embodiment of the invention shown inthe drawings, however, a conventional valve element 198 is threaded intothe upper end of the passage 196.

In order to facilitate retraction of the piston rod 170, the upper endthereof is threaded, and has an eye member 200 threaded thereon. The eyemember 200 is secured in place by a lock nut 202. Compressed air in theregion above the piston 178 must, of course, be relieved before thepiston can be withdrawn, and for this purpose, the upper portion of thesidewall 108 has an opening 204 therein, to which a nipple 206 iswelded. A relief valve 208 is connected to the nipple 206, and isoperable to relieve the pressure behind the piston 178.

Compressed air is supplied to the region above the piston 178 from thepressure tank 144, the tank first being filled with compressed air froma suitable source through a supply hose 210 having the mating half 212of a quick disconnect coupling on the end thereof. The valve 154 isopened during such charging to allow the gauge 152 to function, wherebythe desired air pressure can be obtained in the pressure tank. Whencharging is complete, the valve 154 is closed to isolate the pressuregauge 152, and the supply hose 2.10 is disconnected. Then, one end of aninlet transfer hose 214 is connected to the coupling element 156, theother end of the hose 214 being connected to the inlet of a footoperatedflow control valve 216.

The flow control valve 216 is of conventional design, and includes afoot threadle 218 connected to open the valve when it is depressed, thevalve being constructed to close automatically when foot pressure on thethreadle 218 is released. The flow control valve 216 is mounted near thework station for the bricklayer, so that he can easily operate the foottreadle 218. The outlet of the flow control valve 216 is connected tothe inlet of a conventional adjustable regulator 220, which in turn isconnected to a pressure gauge 222. The outlet of the pressure gauge 222is connected to one end of an outlet transfer hose 224, the other end ofthe hose 224 being connected by a quick disconnect coupling to thecenter leg of a T-fitting 226, one of the aligned legs of the fitting226 being secured to a nipple 228 threaded into one end of a collar 230.

The collar 230 is welded within an opening 232 in the upper vesselsection 106, the opening 232 being aligned with a similar opening 234 inthe dished plate 142. One end of a pipe 236 is threaded into the lowerend of the collar 230, and the lower end thereof is welded within theopening 234. Thus, the pipe 236 is sealed from the pressure tank 144,but functions to admit compressed air to the region between the piston178 and the pressure tank 144. Secured to the upper leg of the T-fitting226 is a pressure safety valve 227, set to automatically relieve excesspressure in the pressure vessel.

Mortar fed from the pressure vessel 102 is supplied to a trowel 238 ofsuitable design, which is hand held by the bricklayer and used by him tolay the mortar in the proper location on the base. The trowel 238 isconnected by a flexible hose 240 to the discharge fitting 114, and againconnections are preferably made using conventional quick disconnectcouplings.

To use the mortar pot apparatus of the invention, the split band clamp134 is first loosened, and the upper vessel section 106 is removed,taking with it the piston 178. The charge of mortar 194 is then placedin the lower vessel section 104, after which the upper section 106 isplaced back in position and secured by the clamp 134. The O-ring seal124 effects an air-tight seal, so that the region above the piston 178is in effect a pressure chamber.

The pressure tank 144 is then charged with compressed air to the desiredpressure, after which the hose 210 is disconnected, and the inlettransfer hose 214 is secured to the T-fitting 154. The bleed passage 196is then utilized to remove any air pockets from beneath the piston 178,utilizing the procedure described earlier, and the mortar pot apparatusis ready for use.

The workman grasps the trowel 238 and moves it to where mortar is to beapplied, and thereafter depresses the treadle 218 to open the controlvalve 216. This allows compressed air to flow from the pressure tank 144to the region above the piston 178, the pressure regulator 220functioning to establish a preset, even pressure in the pressure vessel.The resultant pressure on the piston 178 moves the same forwardly,forcing mortar out through the fitting 114, the hose 240, and the trowel238.

For so long as the treadle 218 is held depressed, air pressure will flowinto the region behind the piston 178 at a regulated even rate, causingcorresponding feeding of the mortar at an even rate. The rate of mortarflow is established by adjusting the flow regulator 220. When it isdesired to stop the mortar flow, the treadle 218 is released, and theflow control valve 216 closes. This stops the transfer of pressure tothe pressure vessel 102, thereby stopping further forward movement ofthe piston 178. When it is desired to reinstitute mortar flow, thetreadle 218 is again depressed. Because the region above the piston 178is air tight, the region retains air pressure. Thus, reopening of thecontrol valve 216 will result in a nearly instantaneous restarting ofmortar flow, at an even rate.

It is thus seen that a pressure mortar pot apparatus has been providedthat fulfills all of the objects set forth hereinabove, and which iseffective to greatly increase the efficiency of a bricklayer. The sizeof the pot 100 is of course a matter of choice, but normally it shouldbe sufficiently large to contain the mortar for about 250 bricks.

Obviously, many modifications and variations of the present inventionare possible.

I claim:

1. Apparatus for applying mortar, comprising: a pressure vessel adaptedto receive a charge of mortar; a piston reciprocally mounted within saidpressure vessel,

said piston being mounted on one end of a piston rod,

the other end of said piston rod being slidingly engaged within ahousing carried by said pressure vessel, and extending through theexterior wall of said pressure vessel, said piston rod having an axialbleed passage extending therethrough for bleeding trapped gas frombetween the front face of said piston and said mortar charge; means forselectively closing the outer end of said bleed passage; an annulargasket mounted on the periphery of said piston, said gasket being insliding engagement with the wall of said pressure vessel, and includingan upstanding peripheral lip portion on the rear side of said pistonadapted to form a pressure seal with the said pressure vessel when theregion behind said piston is pressurized, and a depending lip portion onthe front side of said piston adapted to engage the wall of saidpressure vessel and wipe mortar therefrom as said piston advanceswhereby to provide a clean surface for said upstanding peripheral lipportion to slide upon; means for supplying gas pressure to the regionbehind said piston within said pressure vessel whereby to force saidpiston toward said mortar charge; and discharge means on said pressurevessel in front of said piston, and adapted to receive mortar forcedtherethrough by movement of said piston toward said mortar charge.

2. Apparatus as recited in claim 1, wherein said means for supplying gaspressure includes: a' pressure tank; and conduit means connecting saidpressure tank with said region behind said piston, said conduit meansincluding a flow control valve, and a pressure regulator disposed behindsaid flow control valve and adapted to establish a Preset, substantiallyeven pressure behind said piston.

3. Apparatus as recited in claim 2, wherein said pressure tank isdisposed within said pressure vessel.

4. Apparatus as recited in claim 1, wherein said pressure vessel is madein two parts secured together to form an air-tight vessel, whereby saidparts can be separated to place said mortar charge within said vessel.

5. Apparatus for applying mortar, comprising: a pressure vessel,including a generally cylindrical lower section having an externalflange on its upper end and adapted to receive a charge of mortar, anupper section having a flange on its lower end adapted to mate with theflange on said lower section, and removable clamp means engageable withsaid flanges for securing said sections in assembled relationship; ahousing carried by said upper section; a piston rod reciprocallyreceived within said housing, the upper end of said piston rod extendingthrough said upper section to the exterior thereof; a piston mounted onthe lower end of said piston rod, and receivable within said generallycylindrical lower section above said mortar charge; an annular gasketcarried by said piston, and engageable with the sidewall of said lowersection; means for supplying gas pressure to the region behind saidpiston within said pressure vessel, whereby to force said piston towardsaid mortar charge; and mortar discharge means mounted on said lowersection.

6. Apparatus as recited in claim 5, wherein said piston rod has a bleedpassage extending therethrough from the front of said piston to theexterior of said vessel, and further including means at the outer end ofsaid bleed passage for selectively closing the same.

7. Apparatus as recited in claim 5, wherein said gasket includes: anupstanding peripheral lip portion on the upper side of said piston,engageable with the sidewall of said generally cylindrical lower sectionto form a pressure seal therewith when the region within said pressurevessel above said piston is pressurized; and a depending lip portion onthe lower side of said piston adapted to engage the wall of saidpressure vessel and wipe mortar therefrom as said piston advances,whereby to provide a clean surface for said upstanding peripheral lipportion to slide upon.

8. Apparatus as recited in claim 5, wherein said means for supplying gaspressure includes: a pressure tank contained within said upper vesselsection; and conduit means connecting said pressure tank with the regionof said pressure vessel above said piston, said conduit means including:a flow control valve; and a pressure regulator disposed between saidflow control valve and said region of said pressure vessel.

9. Apparatus as recited in claim 8, wherein said flow control valve isfoot operated.

10. Apparatus as recited in claim 8, including additionally pressurerelief valve means connected with said region of said pressure vessel,and operable to relieve pressure behind said piston.

1. Apparatus for applying mortar, comprising: a pressure vessel adapted to receive a charge of mortar; a piston reciprocally mounted within said pressure vessel, said piston being mounted on one end of a piston rod, the other end of said piston rod being slidingly engaged within a housing carried by said pressure vessel, and extending through the exterior wall of said pressure vessel, said piston rod having an axial bleed passage extending therethrough for bleeding trapped gas from between the front face of said piston and said mortar charge; means for selectively closing the outer end of said bleed passage; an annular gasket mounted on the periphery of said piston, said gasket being in sliding engagement with the wall of said pressure vessel, and including an upstanding peripheral lip portion on the rear side of said piston adapted to form a pressure seal with the said pressure vessel when the region behind said piston is pressurized, and a depending lip portion on the front side of said piston adapted to engage the wall of said pressure vessel and wipe mortar therefrom as said piston advances whereby to provide a clean surface for said upstanding peripheral lip portion to slide upon; means for supplying gas pressure to the region behind said piston within said pressure vessel whereby to force said piston toward said mortar charge; and discharge means on said pressure vessel in front of said piston, and adapted to receive mortar forced therethrough by movement of said piston toward said mortar charge.
 2. Apparatus as recited in claim 1, wherein said means for supplying gas pressure includes: a pressure tank; and conduit means connecting said pressure tank with said region behind said piston, said conduit means including a flow control valve, and a pressure regulator disposed behind said flow control valve and adapted to establish a Preset, substantially even pressure behind said piston.
 3. Apparatus as recited in claim 2, wherein said pressure tank is disposed within said pressure vessel.
 4. Apparatus as recited in claim 1, wherein said pressure vessel is made in two parts secured together to form an air-tight vessel, whereby said parts can be separated to place said mortar charge within said vessel.
 5. Apparatus for applying mortar, comprising: a pressure vessel, including a generally cylindrical lower section having an external flange on its upper end and adapted to receive a charge of mortar, an upper section having a flange on its lower end adapted to mate with the flange on said lower section, and removable clamp means engageable with said flanges for securing saId sections in assembled relationship; a housing carried by said upper section; a piston rod reciprocally received within said housing, the upper end of said piston rod extending through said upper section to the exterior thereof; a piston mounted on the lower end of said piston rod, and receivable within said generally cylindrical lower section above said mortar charge; an annular gasket carried by said piston, and engageable with the sidewall of said lower section; means for supplying gas pressure to the region behind said piston within said pressure vessel, whereby to force said piston toward said mortar charge; and mortar discharge means mounted on said lower section.
 6. Apparatus as recited in claim 5, wherein said piston rod has a bleed passage extending therethrough from the front of said piston to the exterior of said vessel, and further including means at the outer end of said bleed passage for selectively closing the same.
 7. Apparatus as recited in claim 5, wherein said gasket includes: an upstanding peripheral lip portion on the upper side of said piston, engageable with the sidewall of said generally cylindrical lower section to form a pressure seal therewith when the region within said pressure vessel above said piston is pressurized; and a depending lip portion on the lower side of said piston adapted to engage the wall of said pressure vessel and wipe mortar therefrom as said piston advances, whereby to provide a clean surface for said upstanding peripheral lip portion to slide upon.
 8. Apparatus as recited in claim 5, wherein said means for supplying gas pressure includes: a pressure tank contained within said upper vessel section; and conduit means connecting said pressure tank with the region of said pressure vessel above said piston, said conduit means including: a flow control valve; and a pressure regulator disposed between said flow control valve and said region of said pressure vessel.
 9. Apparatus as recited in claim 8, wherein said flow control valve is foot operated.
 10. Apparatus as recited in claim 8, including additionally pressure relief valve means connected with said region of said pressure vessel, and operable to relieve pressure behind said piston. 